Social constructionism is influential in many areas of scholarship concerning such aspects of the human experience as race, gender, therapy, disability, health and illness. However, these ideas have rarely been applied to the understanding of the lives of men and women with learning disabilities. This paper examines some of the central ideas of social constructionism and their application to the construction of knowledge about learning disability by professionals. It examines the constructionist perspective concerning essentialism, realism and the relationship between language and social action as these relate to learning disability. These ideas are then developed further through the application of four assumptions (Gergen, 1985) about social constructionism to learning disability.